The invention relates to a method of manufacturing cooling blocks for semiconductor lasers, which cooling blocks have at least two surfaces intersecting each other along a straight line, the rounding-off radius between said two surfaces having a small value.
It is known that semiconductor laser elements must be cooled very thoroughly so as to obtain a sufficiently long life. For that purpose, the laser element must be connected to a cooling block throughout its length via a low thermal resistance connection.
In many applications of semiconductor lasers it is desirable for the laser element to be accommodated very close to the edge of the cooling block, that is to say, a laser mirror is located at most a few microns from a side face of the cooling block. This is necessary, for example, to obtain an efficient optical coupling with a mono-mode fiber for use in optical communication. This location is also necessary to avoid reflections at the surface of the cooling block.
In very accurate machining techniques, for example, electro-erosive metal removing, the radius of the rib of, for example, a cubical cooling block will still have a value of 20 microns or more. In mechanical machining processes the radius is larger, while furthermore a slight crumbling away of the rib may take place and burring may occur.
When in a cooling block, the rounding-off radius of the rib is 20 microns or larger, a mirror of the laser element is present at a distance of a few microns from the side wall, a part of the laser element will make at best a poor thermal contact with the cooling block, which adversely influences the life of the device.